Interlocking system for railroads



Feb. 28, 1939. A. LANGDON INTERLOCKING SYSTEM FOR RAILROADS 8 Sheets-Sheet 1 Filed Nov. 26, 1937 INVENTOR ZM WZZ 1 ATTORNEY A. LANGDON Feb. 28, 1939.

INTERLOCKING SYSTEM FOR RAILROADS Filed Nov. 26, 1957 8 Sheets-Sheet 2 INVENTOR MLWM Y ATTORNEY A. LANGDON Feb. 28, 1939.

INTERLOCKING SYSTEM FOR RAILROADS Filed Nov. 26, 1937 s Sheets-Sheet s INVENTOR BY M ATTORNE TV TV fill x? 25 a Ouv ZWP

A. LANGDON 2,148,865

INTERLOCKING SYSTEM FOR RAILROADS Feb. 23, 1939.

Filed Nov. 26, 1937 a Sheets-Sheet 4 INVENTOR Feb. 28, 1939. A. LA NGDON 2,148,865

I INTE RLOCKING SYSTEM FOR RAILROADS Filed Nov. 26, 1937 I 8 Sheets-Sheet 5 I INVENTOR 3 LE & E N /4;;,M0RNEY Feb. 28,1939. A N.

I INTERLOCKING SYSTEM FOR RAILROADS 8 Sheets-Sheet 6 Filed Nov. 26, 1937 n mmmul tlLlFTIJ TV mzh l i 20 m fi w +v N; 2

INVENTOR A. LANGDON INTERLOCK'ING SYSTEM FOR RAILROADS Feb. 28, 1939.

8 Sheets-Sheet '7 Filed Nov. 26, 1937 INVENTOR MM M MTORNEY @Zmo QXMQ ooms rlll ln I01.

Feb. 28, 1939. I v A. LANDON 2,148,865

7 INTERLOCKING SYSTEM FOR RAILROADS Filed Nov. 26, 1957 8 Sheets-Sheet 8 Z INVOEZJ TOR Patented Feb. 28, 1939 v UNITED STATES PATENT OFFIQE Andrew Langdon, Brighton, N. Y., assignor to General Railway Signal Company, Rochester,

Application November 26, 1937, Serial No. 176,466

21 Claims.

This invention relates to electric interlocking systems for railroads, and more particularly pertains to an interlocking system of the entranceexit type.

The entrance-exit type of interlocking system of the present invention is to be considered an improvement over my prior application Ser. No. 119,641, filed January 8, 1937.

In a system of this character, the trafiic controlling devices of an interlocking plant are controlled from a central oflice having a control machine with a control panel upon which is located a miniature track diagram corresponding to the actual track layout of the plant. On this combined miniature track diagram and control panel are located initiating and completing buttons for the ends of the routes. The actuation of an initiating button and a completing button at the opposite ends of aparticular route, causes the 90 operation of all of the track switches to proper positions to establish that route and also causes the clearing of the signal after the route has been established.

One of the objects of the present invention is to provide such entrance-exit control through the medium of a so-called, self-selecting network which is organized upon the basic fact that each track switch of an interlocking plant is trailed by traffic movements in a particular direction for that switch. If we choose an entrance point at one end of the interlocking plant, and consider all of the available routes emanating from that point in such a way as to move all of the switches which are trailed for that direction Q3 in such available routes, and then choose an exit point where we wish to leave the plant returning towards the chosen entrance point moving all of the switches which are trailed for that direction, we find that the trailing switches for the first direction are facing switches for the opposite direction and have been properly positioned to definitely select the returning route. The entire and complete route between the chosen entrance point and the chosen exit point is thus J definitely established.

In accordance with the present invention, the.

principles of the preceding paragraph are applied to a self-selecting network so that the actuation of the initiating (or entrance) button for a given entrance point positions control selecting relays for each of the track switches in the track layout which have a trailing switch point movement relation to that entrance point. With all such control selecting relays thus positioned, the actuation of the completion (or exit) button &

for a particular exit point then positions switch control relays for each switch in the particular route between such entrance and exit points dependent upon the selecting relays to cause the track switches to be power operated to proper positions for that route.

One object of the present invention is to provide a network, organized in accordance with the above mentioned principles, in such cooperation with the traffic conditions in the track layout that a route once established and accepted by a train will cause the switch control relays of the self-selecting network to be maintained in their actuated conditions although the governing entrance button for that route is returned to stop or a non-controlling position. This relationship between the self-selecting network and the trafiic conditions provides that the relays conditioned for the establishment of a particular route may be maintained so as to prevent a conflicting route from being established so long as a train is in that particular route.

The feature of maintaining the network in accordance with the route established is accomplished by the invention in such a way, that, as the train passes through the route, the control relays for the track switches in the rear of the train are released to allow such track switches to be employed for the establishment of new routes.

A still further object of the present invention is to so organize the self-selecting network with respect to the controlling of the track switches and signals that the completion of the manipulation for a particular route causes the operation and locking of all of the track switches in such route before the signal governing that route can be cleared.

A still further feature of the present invention is to provide the above described entrance-exit control in such a manner that the track switches are not only controllable by the composite or collective network route control, but may also be actuated to their different positions by individual I In describing the invention in detail, reference will be made to the accompanying drawings, in which like letters in the reference characters designate similar functions or relationships with the distinctiveness between such reference characters provided by the use of distinctive preceding numerals; in which like preceding numerals in the reference characters when applied to different letters represent the inclusion of such devices within a particular group; and in which:

Figs. 1A and 1B, when placed end to end, show the miniature track diagram and self-selecting network for a track layout shown in detail in Figs. 4A and 4B;

Fig. 2 shows a typical switch control circuit for one of the crossovers in the track layout shown in Figs. 4A and 43, with the specific signal selections associated with that particular crossover;

Figs. 3A and 313, when placed end to end, show the route locking circuits for the particular track layout selected for the embodiment of the present invention;

Figs. 4A and 4B, when placed end to end, show the track layout and signal control circuits for the embodiment of the present invention; and

Fig. 5 discloses a self-restoring entrance button and. its control as employed with the self-selecting network of the present invention in place of the entrance buttons employed in Figs. 1A, and 115.

For the purpose of simplifying the illustration and facilitating in the explanation thereof, the conventional parts and circuits constituting the embodiment of the invention have been shown diagrammatically and certain conventional illustrations have been employed, the drawings having been made more with the purpose of making clear the principles and objects of the present invention together with its mode of operation, than with the idea of illustrating the actual construction and arrangement of parts that would probably be employed in practice.

The various relays and their contacts are i1- lustrated in a conventional manner and symbols are employedto indicate connections to the terminals of batteries, or other suitable sources of electrical current supply, instead of showing all the wiring connections to such terminals.

The symbols and are employed to indicate the positive and negative terminals respectively of suitable batteries or other source of electrical energy; and those terminals with which these symbols are used are assumed to have current flowing from the positive terminal designated to the negative terminal designated The symbols employed with any one circuit are considered to designate the terminals of the same battery, or other suitable source, but it is to be understood that as many separate sources may be provided as found necessary, or as many sources may be combined into a single source as found expedient in the practicing of the invention.

If alternating current is employed instead of direct current, the symbols should be considered to represent the instantaneous relative polarities of the respective terminals;

Where groupsof devices are referred to in a general way, the letter reference characters will be used to designate such groups instead of mentioning each specific reference character of that group.

Apparatus Track Zayout.With reference to Figs. 4A and 4B, the present invention has been shown as applied to a stretch of double track interconnected by crossovers and having turnout track switches. These crossovers and track switches include track switches ZTSA ZTSB, 3T5, TSA-ATSB, 5T SA5TSB, and are.

The track switches are operated by power switch machines which may be of any suitable type, such for example, as shown in the patent to W. K. Howe, Patent No. 1,466,903, dated September 4, 1923. However, the motor of each switch machine is preferably controlled as shown for example, in the patent to W. H. Hoppe, et al., Patent No. 1,877,876, dated September 20, 1932, with the relay CR of such patent controlled by the relay WZ of this disclosure as more specifically shown in Fig. 2.

Each track switch TS is suitably controlled by its power operated switch machine SM. Inasmuch as the opposite ends of a crossover are usually operated at the same time, only a single switch machine SM has been shown as operating each crossover, although it is to be understood that aseparate switch machine may be employed for each of the two track switches of a crossover when desired. More specifically, the switch machine ZSM operates the track switches ZTSA and ZTSB; switch machine 3SM operates the switch 3T8; switch machine lSM operates track switches ATSA and QTSB; switch machine 58M operates track switches ETSA and 5TSB; and switch machine BSM operates track switch ETS.

Associated with each of the track switches and its respective switch machine is a suitable relay WP of the polar neutral type. Each relay WP is energized with one polarity or the other in accordance with the normal or reverse locked position of its track-switch in correspondence with its switch machine SM, and is deenergized whenever its track switch is in operation or is unlocked. The polarized circuit for controlling each switch position relay WP is governed by its track switch TS and switch machine SM through the medium of a point detector contact mechanism, such as shown for example in the patent to C. S. Bushnell, Patent No. 1,517,236, dated November 25, 1924. It is to be understood that when two switch machines are employed for a crossover that there would probably be two such point detector contact mechanisms and that the contacts of each would be suitably included in series in the polarized circuit for the relay WP for such crossover so that both of the track switches of the crossover must be in corresponding positions and locked in order for the relay WP to be energized.

Signals IOI, I02, 583 and HM are provided for governing east-bound traffic at the west entrance to the track layout, while'signals I05 and I06 are provided at the east end of the track layout to govern west-bound traffic.

The various signals are assumed to be color light signals giving the usual indications of green for clear and red for danger or stop, and yellow '11 an added indication is desired for caution. It

with the usual track relays T and track batteries, of which the track relays I2T, MT, HT and ST have been shown. The number of track circuits is determined in accordance with the usual principles of signalling in such a way that there is at least one track circuit for each parallel or non-conflicting route. These track circuits are assumed to be of the'normally energized type and are wired in the usual manner to provide for fouling protectionand to provide for the insulation of the track switches and crossovers, such details having been omitted for the sake of simplicity in the disclosure. Control machine-With reference to Figs. 1A and IE, it will be seen that the control machine is contemplated as including a miniature track layout corresponding to the actual track layout in the field (see Figs. 4A and 4B) The construction of the miniature track diagram on the control panel may be of any suitable type employing either miniature movable switch points as representative of the track switches, or employing illuminated. sections of trackway such as shown and described in the prior application of F. B. Hitchcock, Ser. No. 74,709, filed April 16,1936, thislatter form being chosen for the present embodiment.

One of the features of an interlocking system contemplated in accordance with the present invention is the location of entrance and exit buttons on the control panel in such a way that they designate the entrance and exit points on the miniature track diagram. More specifically, an entrance button NB is provided for each of the signal locations, such as entrance buttons IMNB, IUZNB, I03NB, HMNB, I05NB and lliSNB, these buttons being for the respective signals indicated by their preceding numerals. An exit button is provided for the exit end of each route, such as exit buttons IMXB, IUZXB, I03XB, IMXB, HISXB and -l06XB, it being assumed that the ends of the routes with which they are associated coincide with the signal locations indicated by their preceding numerals However, it is to be understood that the ends of the routes may or may not correspond to the locations of the exit buttons XB on the control panel, as a route is usually considered to extend from a particular signal to the nextsignal governing trafiic inthe same'direction, or at least to some arbitrarily chosen point which may or may not coincide with the next signal for the opposing direction.

. The present invention contemplates that each entrance button NB is in the form of a knob which may be rotated 90 from a normal position to an operated position so that its index coincides with the fixed arrow on the signal indicator lamp located within the button, thus indicating that such signal is to allow for the passage of trafiic when its indicator is illuminated. This type ofentrance button remains in the position to which it is actuated so that when a signal has been cleared and a train has accepted such signal, the button must be manually .restored to its normal position. Each entrance button NB is'provided with suitable contacts which are closed when the button, is in the norin any suitable way and still be within the scope of the present invention. For example, the en-' trance and exit buttons NB and KB may be physically combined in such a Way that the rotation of the knob actuates the entrance contacts while the depression of the knob actuates the exit contacts.

It may be well to point out here that the present invention also contemplates that self-restoring entrance buttons may be employed in place of the stay-where-put entrance buttons of Figs. 1A and 13. Such a self-restoring entrance button and its control has been shown in Fig. 5,

,where each such self-restoring entrance button requires a repeating relay GZ which can be picked up upon the momentary actuation of its entrance button and can be maintained stuck up until the acceptance of a signal by a train.

The control machine also includes an auxiliary switch control lever SML for each of the power operated switch machines, only one of which has been shown (see Fig. 2). These switch machine control levers SML are for the purpose of controlling the individual track switches under certain emergency conditions such as to operate them to free the switch points from ice or lumps of coal, and also at such times as certain optional or run-around routes are desired at times when such routes are not rendered automatically available by the self-selecting network.

A correspondence lamp COR is associated with each of the auxiliary switch machine control levers SML to indicate when the corresponding track switch is in correspondence with its control as provided either by the self-selecting network or by the individual switch machine control lever SML. Each lamp COR is unilluminated when correspondence exists and is illuminated when there is a lack of correspondence.

Although the structural details of the minia ture track diagram have not been shown, it is contemplated in accordance with the present invention that each of the miniature track switches shall have associated therewith indicator lamps whlchare controlled in accordance with the positions of the track switch and in accordance with the locked condition of such track switch. These indicator lamps may illuminate extended portions of miniature trackway or just portions located adjacent the miniature track switches which are represented on the miniature trackway as shown in Figs. 1A and 1B, but their control has been typically illustrated in connection with the indicator lamps 4ANK, lPvK and QBNK of Fig. 2.

System deoices.-The entrance buttons NB and the exit buttons XB, as above mentioned, are respectively indicated as connected to their contacts in Figs. 1A and 113. But there are contacts 7 on each of the entrance buttons NB in Figs. 4A

and 4B which, due to the organization of the drawings, are not connected by dotted lines to their respective entrance buttons but have been designated as associated therevw'th by the entrance button nomenclature. Each exit button XB has associated therewith an exit relay KB.

The contacts of the entrance button NB for one end of a route and the contacts of the exit relay XR for the opposite end of that route jointly! control the positioning of the proper switch control relays for the switches and crossovers in that route.

For each crossover, switch control relays AN, R and EN (with suitable preceding numerals) are employed, while for each single switch, control relaysN and R (with suitable preceding numerals) are employed. These relays are of the neu-v tral type and govern the operation of their respective; switch machines through the medium of a. polar neutral relay WZ having oppositely connected windings. These switch control relays are selected through the self-selecting network including auxiliary relays Z, certain ones of which are termed AZ and B2 when associated with a crossover. These auxiliary relays Z condition the circuits of the self-selecting network in such a manner that the energization of the N and R relays in sequence causes the sequential operation of the track switches, as will be more specifically pointed out hereinafter.

In Figs. 3A and 133, route locking, relays ES and WS have been shown with their respective control circuits governed in accordance with the G relays which control their respective signals as designated by their preceding numerals. These route locking relays are so organized that each track circuit is provided with two such relays, one for each direction. For example, the track circuit having track relay I2T (see Fig. 4A) has shown associated therewith the route locking relays I2ES- and IZWS.

Each track circuit has associated therewith a lock relay L which prevents the operation of the track switch or switches in its section when traflic conditions make it unsafe for such operation. These look relays have been shown in Figs. 3A and 3B for each of the track sections. In brief, each lock relay such as IL, for example, includes contacts of its associated track section and contacts of the route locking relays for such track switches all being selected through such lock relay.

However, if it is desired to have an individual lock relay for each track switch, such lock relay foreach switch may readily be provided with duplicate selections on the track relay and route locking relays of the track section in which such switch is located. The contacts of the several auxiliary switch control levers are of course allotted to the lock relays of their respective track switches. This change in the preferred form of lock. relay control gives the same locking sofar as traflic conditions are concerned, but the locking; resulting from the; operation of an auxiliary switch control lever is of course individual to its track switch.

Although the route locking circuits of Figs. 3A and. 3B have been shown in their simplest form, it is to be understood that suitable approach locking features and time release therefor may be employed in connection with such route looking, allin a manner as more specifically shown and described in the prior patent granted to E. C. Larry et al., Patent No. 2,125,242 dated July 26, 1938, but it is believed to be unnecessary for an understanding of the present invention to show such features in detail.

Associated with each of the track switches is a lock stick relay, shown specifically as relay lLS for the switch machine 48M in Fig. 2. This lock stick relay LS isprovided to maintain energy upon. the switch machine so long, as its track switch isbeing, operated. or is unlocked, and; to

messes remove; energy from the switch machine when, it islocked to permit the closing of the signal clearing; circuits.

Each track switch has. associated with its control relays N and R and its relay.- W]? two.= correspondence relays NCR and. RCR one or the other of which is energized. when such track switch is in correspondence with its manual control andbothof which are deenergized whenever the track switch isout of correspondence or is in operation. It may be wellto note, however, that one or the other of the correspondence relays NOR or RCR is energized depending upon the. position and looked condition of its track switch when there is no manual control present-for such track switch. In other words, the correspondence condition is indicated: with regard to the manual control only when there is such manual control actually present for the track switch.

With reference to Figs. 4A and 413, a signal control relay G- is provided for each signal, for causing that signal to indicate clear or stop. These signal controlrelays havebeen specifically shown for each of the signals in the track layout and the selecting circuits have been shown in detail. However, dotted lines connecting such relays with their respective signals have been employed instead of showing. the detailed" circuits, it being readily understood that each relay when deenergized causes-itsassociated signal to indicate red or stop, and when energized causes its; associated signal to indicate green or clear.

It is believed that the remaining featuresof the present invention will be best understood;v by considering certain typical operations in detail.

Operation Normal conditions-The track switches. of an interlocking plant: controlled by the system of the present invention are left in-their last operated positions, but forconvenience in the disclosure they have been shown in their main line. or normal positions. The signals are considered to v be normally at stop with the lower or red indicator of: each signal illuminated, unless asmight bev employed in practice, certain approach light features are employed;

All of the track circuits are considered to be unoccupied so that their respective track relays T are normally picked up.

All' of the lock. relays L shown are normally energized as will be readily apparent. from the consideration of the lock relays ML. and |5L of Fig. 2.

All of the switch control relays N and R of the self-selecting network of Figs. 1A and 1B are normally deenergized.

In. providing the indications on the control panel, although only certain onesof such indications have been shown in the present disclosure, it is preferable that they be arranged so as to give a normally dark board However, any desired arrangement may be employed within the scope of the present invention.

.Self selecting netwoflc.When the operator desires to set up a route, as for example, between thesignals I01 and I06; he actuates the entrance button HHNB to an operated position followed by the momentary actuation. of the exit button IOGXB.

The. operation of the entrance button IBINB causesv the; energization of the, Z relay for each track: switch. which is. trailed in all of the. routes emanating from the signal Hll providing such trailing movementis for a,- preferredor particular position of such track switch. For the purpose of the present disclosure, the preferred or particular position of each track switch has been assumed to be the position for setting up a route over the main line or straight track, which position is conveniently termed the normal position in this description; but, the preferred or particular position of each track switch can be, if desired, the position for setting up a diverging route, which position is conveniently termed the reverse position in this description.

Following the positioning of the Z relays in response to the operation of the entrance button, the actuation of the exit button causes the energization of its exit relay, providing that there is no conflicting route which will be considered more in detail hereinafter, which exit relay applies energy to circuits selected by the relays Z to energize a switch control relay N or R for each of the track switches in that particular route connecting the designated entrance and the exit points.

Let us apply these principles of the present invention to the particular route under consideration as extending from the signal IDI to the signal I 06. The relay 3Z for the track switch 3T8 is not picked up inasmuch as a movement from v the signal IGI is for trailing such track switch 7 button HQENB in a normal position, to

in its reverse position. The relay 4A2 is not energized because the track switch 4TSA is facing for a route emanating from signal I [II and extending to signal I06. The relay 4BZ is not energized because it is trailed reverse. But the relay 5AZ is energized, because it is trailed normal fora route emanating from signal I! to signal I05. The relay 5BZ is not energized because its track switch 5TSB is facing in the rout-e emanating from signal I Ill and extending to signal I66. The relay 6Z is energized inasmuch as the track switch 6T8 is trailed normal in the route emanating from signal I! and extending to signal I66.

' 'More specifically, the relay AZ is energized by a circuit closed from through a circuit including contact 20 of entrance button I eINB in an operated position, back contact 2| of relay IIHXR, back contact. I9 of relay 3N, back contact 22 of relay 3Z, wire 23, back contact 24 of relay 4R, back contact 25 of relay 5R, winding of relay 5AZ, to

- The relay 6Z is energized by a circuit closed from through a circuit including contact 20 of entrance button IlIlNB in an operated posi- .tion, back contact 2| of relay IBIXR, back coning contact 26 of entrance button IOINB in an operated position, back contact 2! of relay I6 IXR, back contact I9 of relay 3N, back contact 22 of relay 3Z, wire 23, back contact 26 of relay 4AN, back contact 2'! of relay 4BN, back contact 28 of relay4BZ, back contact 25 of relay 5R, back contact 30 of relay 6R, front contact 3| of relay 6Z, windingsof relay 565KB, back contact 32 of exit button iilBXB, back contact 33 of entrance As soon as the exit relay IllGXR picks up, it closes front contact 34, which applies negative-potential to the right hand terminal of the relay I06XR, so that the exit button IIIBXB may be immediately released.

The picking up of the relay IOSXR closes an energizing circuit for the relay 6N, inasmuch as the relay 6Z is picked up, from through a circuit including front contact 35 of relay I06XR, front contact 36 of relay 6Z, upper winding of relay 6N, back contact 31 of relay 6R, to

Upon the response of relay 6N, a circuit is closed for energizing the relay 5BN from through a circuit including front contact 35 of relay IDGXR, front contact 36 of relay 6Z, front contact 38 of relay 6N, upper winding of relay 5BN, back contact 39 of relay 5R, to

An energizing circuit is closed for the relay 4B, When relay 5BN picks up, from through a circuit including front contact 35 of relay IOGXR, front contact'36 of relay 6Z, front contact 38 of relay 6N, front contact 40 of relay 5BN, back contact 4| of relay 4BZ, upper winding of relay 4R, back contact 42 of relay 4AN, back contact 43 of relay 4BN, to

As soon as the relay 4R picks up it opens back contact 24 which deenergizes the relay 5AZ by opening its circuit previously pointed out.

The picking up of the relay 4R also completes a circuit for the relay 3R from through a circuit including front contact 35 of relay IBBXR, front contact 36 of relay 6Z, front contact 38 of relay 6N, front contact 40 of relay 5BN, back contact 4! of relay 432, front contact 44 of relay 4R, wire 45, back contact 46 of relay 32, upper winding of relay 3R, back contact 41 of relay 3N, to

It will thus be seen that the relays N and R for the route from signal IUI to signal I66 have been selectively energized in succession. This sequential energization of the switch control relays for a route has been conveniently termed a uniform cascade arrangement.

Operation of track switches The energization of a normal or a reverse relay N or R for a track switch causes the corresponding normal or reverse operation of such track switch through the medium of suitable control circuits which have been typically illustrated in connection with the crossover including track switches 4TSA and 4TSB (see Fig.2)

With the track switches 4TSA and 4TSB in normal positions, the relay 4WP is of course energized with a particular polarity causing its polar contacts to assume normal right-hand positions and its neutral contacts to be picked up. Under such conditions the normal correspondence relay 4NCR is energized regardless of the presence or absence of a normal control for the switch machine 4SM. In other words, the relay 4NCR is energized when one, the other, or both of the relays 4AN and 4BN are energized, or when both are deenergized. This circuit for the relay 4NCR is closed from through a circuit including back contact 50 of relay 4R, windings of relay 4NCR, polar contact 5| of relay 4WP in a righthand position, front contact 52 of relay 4WP, to

Similar control is provided for the reverse correspondence relay 4RCR so that if the track switches 4TSA and 4TSB are in reverse positions, the relay 4RCR is energized irrespective of whether there is a reverse control present or not. Assuming that such a reverse condition of the track switches 4TSA and 4TSB is existing, there is an energizing circuit for the relay 4RCR closed from through a circuit including back contact 53' of relay AAN, back contact 54 of relay 4BN, windings of relay 4RCR, polar contact 5| of relay 4W]? in a left-hand position, front contact 52 of relay GWP, to

Under the route control above considered where relay dB is picked up by the self-selecting network, it will be apparent that the opening of back contact 58 of relay 4R immediately deenergizes the relay GNCR so that its contacts drop away. At the same time that the contacts of the relay 4NCR are dropping away, front contact 5!] appliesenergy from through the lower reverse winding R of the relay iWZ, to This energization of the relay 4W2 causes its polar contacts to be operated to left-hand positions and its neutral contacts to be picked up. Under normal conditions with no route set up, the lock stick relay ALS is energized through its pick-up circuit from through a circuit including front contact 55 of relay I5L, front contact 56 of relay ML, back contact 51 of relay 4WZ, windings of relay 4L5, to

It will be noted that the picking up of the relay 4W2 in response to the switch control relay 4R, opens the back contact 51 in the pick-up circuit for the lock stick relay 4L8 so that this look stick relay would drop away if it were not for its stick circuit which is made up by the dropping of the contacts of the relay dNCR. This stick circuit for the relay 4LS is closed from through a circuit including front contact 55 of lock relay ISL, front contact 56 of lock relay ML, front contact 58 of relay 4L8, back contact 59 of relay 4RCR, back contact 60 of relay dNCR, windings of relay 4 LS,to

inasmuch as the contacts of the relay 4L8 are maintained picked up with the neutral contacts of the relay 4WZ picked up, then reverse energy is placed upon the switch machine 4SM from through a circuit including polar contact 6! of relay ZWZ in a left-hand position, front contact 62 of relay 4W2, front contact 63 of relay 4LS, through the windings of the master relay (not shown) in the switch machine 43M, front contact 64 of relay 4LS, front contact 65 of relay 4W2, polar contact 66 of'relay WZ in a left-hand position, to This energization of the switch machine 48M causes it to unlock the track switches eTSA and 4TSB and operate them to reverse locked positions. While these track switches are unlocked and are in operation, the relay 4WP is deenergized. The open condition of front contact 52 of relay 4WP of course maintains the correspondence relays 4RCR and QNCR deenergized, while the closure of back contact 61 of relay 4WP closes a stick circuit for the relay 4WZ from through a circuit including back contact 61 of relay 4WP, front contact 68 of relay 4W2, polar contact 69 of relay 4W2 in a left-hand position, lower reverse Winding R of relay 4WZ, to This application of energy to the reverse winding R of relay 4WZ maintains the relay 4W2 energized to complete the operation of the switch machine 4SM in the event that the relay 4R should be deenergized due to the operator changing his mind with regard to the establishment of the route and therefore returning the entrance button IBINB, for example, to its normal position.

Upon the completion of the operation of the track switch-es 4TSA and lTSB to their reverse locked positions, the relay iWP is energized with the opposite polarity actuating its contacts to lefthand positions and causing its neutral contacts to be picked up. This energizes the reverse correspondence relay 4RCR through the circuit above pointed out. The picking up of contact 59 of relay lRCR opens the stick circuit for the relay iLS so that with the relay 4WZ still picked up opening back contact 51, the relay 4LS is entirely deenergized and its contacts drop away. The opening of front contacts 63 and 64 of relay LS removes energy from the switch machine 38M and the closure of the back contact 63 shunts the control wires through an obvious circuit.

If the switches @TSA and 4TSB had already been in their reverse positions, the reverse correspondence relay iRCR. would have been energized and would have remained energized so that the energization of relay lWZ by relay 4R would cause the immediate deenergization' of relay 4LS at back contact iii. Similar operation would;

occur upon the energization of either or both of the relays LAN and BN with the track switches iTSA and l-TSB in normal positions, as the relay iNCR, would remain energized so that the opening of back contact 51 of relay 4WZ would cause immediate deenergization of relay 4L8.

The above description points out the operation of the track switches ETSA and @TSB by the switch maohine iSM which is controlled in accordance with the normal and reverse switch control relays iAN, 5E and iBN. However, it is to be understood that the track switches 2TSA and ZTSB are operated by the switch machine ZSM similarly controlled by the normal and reverse switch control relays EAN, ER and ZBN. Similarly, the switch machine 38M is controlled by the switch control relays 3N and 3B. 'Also, the switch machine 58M is controlled by the switch control relays SEN, ER and SAN; while the switch machine $8M is controlled by the relays 6N and ESE, It is believed that these various controls may readily be understood by anal ogy to the switch machine control typically shown in Fig. 2 of the accompanying drawings.

Signal control With reference to Figs. 4A and 413, it will be seen that with the entrance button iEiiNB in an actuated position and the exit relay IQGXR picked up, energy can be applied to the signal clearing relay HUG as soon as the correspondence relays for the various switches assume proper positions for the route in accordance with the set up condition of that route and as soon as the lock stick relays for all of the track switches in the route drop away indicating the completely locked condition of such track switches.

Assuming that each of the track switches in the route from the signal. Nil to the signal I06 have been properly positioned and. locked, as pointed out typically in connection with the crossover including track switches QTSA and dTSB, there is an energizing circuit closed for the relay ifiiG from through a circuit including lever contact "at of entrance button IfiBNB in a non-operated position, front contact ll of relay IilfiXR, back contact 2'2 of relay tLS, front contact 13 of relay fiNCR, front contact M of relay ENCR, back contact 75 of relay 5L8, back contact it of relay @LS, back contact 1'! of relay QNCR, front contact is of relay iRCR, back contact T9 of relay lNCR, back contact 88 of relay 4L8, wire ti, back contact 8-?! of relay 3L5, back contact 83 of relay 3NCR, front contact 84 of relay 3RCR, back contact 85 of relay HIIXR, lever contact 86 of entrance button HHNB in an operated position, winding of relay H'HG, to

position of such track switch. For the purpose ticular position of each track switch has been assumed to be the position for setting up a route over the main line or straight track, which position is conveniently termed the normal position in-this description; but, the preferred or particular position of each track switch can be, if desired, the position for setting up a diverging route, which position is conveniently termed the reverse position in this description.

Following the positioning of the Z relays in response tothe operation of the entrance button,

the actuation of the exit button causes the energization of its exit relay, providing that there is no conflicting route which will be considered more in detail hereinafter, which exit relay applies energy to circuits selected by the relays Z to energize a switch control relay N or R for each of the track switches in that particular route connecting the designated entrance and the exit points.

Let us apply these principles of the present invention to the particular route under consideration as extending from the signal Hll to the signal I06. The relay 32 for the track switch 3TS is not picked up inasmuch as a movement from the signal H is for trailing such track switch in its reverse position. The relay 4AZ is not energized because the track switch 4TSA is facing for a route emanating from signal I0! and extending to signal I06. The relay 4BZ is not energized because it is trailed reverse. But the relay 5AZ is energized, because it is trailed normal for a route emanating from signal In! to signal I05. The relay 5BZ is not energized because its track switch 5TSB is facing in the route emanating from signal I31 and extending to signal I06. The relay 6Z is energized inasmuch as the track switch 6TS is trailed normal in the route emanating from signal I01 and extending to signal I06.

More specifically, the relay 5AZ is energized by a circuit closed from through a circuit including contact 20 of entrance button I (HNB in an operated position, back contact 2| of relay IOIXR, back contact IQ of relay 3N, back contact 22 of relay 3Z, wire 23, back contact 24 of relay 4R, back contact 25 of relay 5R, winding of relay 5A2, to

The relay 6Z is energized by a circuit closed from through a circuit including contact 20 of entrance button HHNB in an operated position, back contact 2! of relay HlIXR, back contact [9 of relay 3N, back contact 22 of relay 3Z, wire 23, back contact 26 of relay 4AN,'back contact 21 of relay 4BN, back contact 28 of relay 4BZ, back contact 29 of relay 5R, back contact 30 of relay 6R, winding of relay 6Z, to

When the operator actuat-es the exit button IDGXB, a circuit is closed for energizing the exit relay IIIBXR, from through a circuit including contact 20 of entrance button HHNB in an operated position, back contact 2| of relay l0 IXR, back contact IQ of relay 3N, back contact 22 of relay 3Z, wire 23, back contact 26 of relay 4AN, back contact 21 of relay lBN, back contact 28 of relay 4BZ, back contact 23 of relay 5R, back contact 30 of relay 6R, front contact 3| of relay 6Z, windings of relay HJBXR, back contact 32 of exit button lllBXB, back contact 33 of entrance button lBBNB in a normal position, to As soon as the exit relay IBEXR picks up, it closes front contact 34, which applies negative potential(), to theright hand terminal of the relay IOBXR, so that the exit button I06XB may be immediately released.

The picking up of the relay IHBXR closes an energizing circuit for the relay 6N, inasmuch as the relay 6Z is picked up, from through a circuit including front contact 35 of relay l 06XR, front contact 36 of relay 62, upper winding of relay 5N, back contact 3! of relay SE, to

Upon the response of relay 6N, a circuit is closed for energizing the relay 5BN from through a circuit including front contact 35 of relay l 06XR, front contact 36 of relay 6Z, front contact 38 of relay 6N, upper winding of relay 5BN, back contact 39 of relay 5R, to

An energizing circuit is closed for the relay 4R, when relay 5BN picks up, from through a circuit including front contact 35 of relay HISXR, front contact 36 of relay 62, front contact 38 of relay 6N, front contact 40 of relay 5BN, back contact 41 of relay 4BZ, upper winding of relay 4R, back contact 42 of relay 4AN, back contact 43 of relay 4BN, to

As soon as the relay 4R picks up it opens back contact 24 which deenergizes the relay 5AZ by opening its circuit previously pointed out.

The picking up of the relay 4R also completes a circuit for the relay 3R from through a circuit including front contact 35 of relay I06XR, front contact 36 of relay 6Z, front,contact 38 of relay 6N, front contact 40 of relay 5BN, back contact 4| of relay 4BZ, front contact 44 of relay 4R, wire 45, back contact 46 of relay 3Z, upper winding of relay 3R, back contact 41 of relay 3N, to

It will thus be seen that the relays N and R for the route from signal "H to signal I06 have been selectively energized in succession. This sequential energization of the switch control relays for a route has been conveniently termed a uniform cascade arrangement.

Operation of track switches The energization of a normal or a reverse relay N or R for a track switch causes the corresponding normal or reverse operation of such track switch through the medium of suitable control circuits which have been typically illustrated in connection with the crossover including track switches 4TSA and 4TSB (see Fig. 2).

With the track switches 4TSA and 4TSB in normal positions, the relay 4WP is of course energized with a particular polarity causing its polar contacts to assume normal right-hand positions and its neutral contacts to be picked up. Under such conditions the normal correspondence relay 4NCR. is energized regardless of the presence or absence of a normal control for the switch machine 4SM. In other words, the relay 4NCR is energized when one, the other, or both of the relays 4AN and 4BN are energized, or when both are deenergized. This circuit for the relay 4NCR is closed from through a circuit including back contact 50 of relay 4R, windings of relay 4NCR, polar contact 5| of relay 4WP in a righthand position, front contact 52 of relay 4WP, to

Similar control is provided for the reverse correspondence relay 4RCR so that if the track switches 4TSA and 4TSB are in reverse positions, the relay 4RCR. is energized irrespective of whether there is a reverse control present or not. Assuming that such a reverse condition of the track switches 4TSA and 4TSB is existing, there is an energizing circuit for the relay 4RCR closed from through a circuit including back contact 53 of relay lAN, back contact 54 of relay dBN, windings of relay ARCR, polar contact 5| of relay AWP in a left-hand position, front-contact 52 of relay lWP, to

Under the route control above considered where relay 4R. is picked up by the self-selecting network, it will be apparent that the opening of back contact 5b of relay 4R immediately deenergizes the relay GNCR so that its contacts drop away. At the same time that the contacts of the relay ANCR are dropping away, front contact 50 applies energy from through the lower reverse winding R of the relay AWZ, to This energization of the relay AWZ causes its polar contacts to be operated to left-hand positions and its neutral contacts to be picked up.

Under normal conditions with no route set up, the lock stick relay 4L5 is energized through its pick-up circuit from through a circuit including front contact 55 of relay I5L, front contact 55 of relay ML, back contact 5'! of relay 4WZ, windings of relay ALS, to

It will be noted that the picking up of the relay 4W2 in response to the switch control relay 4R opens the back contact 51 in the pick-up circuit for the lock stick relay 4L8 so that this lock stick relay would drop away if it were not for its stick circuit which is made up by the dropping of the contacts of the relay 4NCR. This stick circuit for "the relay 4L8 is closed'from through a circuit including front contact 55 of lock relay 15L, front contact 56 of lock relay ML, front contact 58 of relay 4L8, back contact 59 of relay 4RCR, back contact 60 of relay 4NCR, windingsof relay ALS, to

Inasmuch as the contacts of the relay 4L8 are maintained picked up with the neutral contacts of the relay 4WZ picked up, then reverse energy is placed upon the switch machine 4SM from through a circuit including polar contact 51 of relay 4WZ in a left-hand position, front contact 62 of relay 4WZ, front contact 63 of relay 4LS, through the windings of the master relay (not shown) in the switch machine "48M, front contact 64 of relay 4LS, front contact 65 of relay 4WZ, polar contact 66 of relay WZ in a left-hand position, to This energization of the switch machine ASM causes it to unlock the track switches ATSA and 4TSB and operate them to reverse locked positions. While these track switches are unlocked and are in operation, the relay 4WP is deenergized. The open condition of front contact 52 of relay 4WP of course maintains the correspondence relays dRCR. and lNCR deenergized, while the closure of back contact 61 of relay 4'WP closes a stick circuit for the relay 4WZ from through a circuit including back contact 6? of relay GWP, front contact 68 of relay 4W2, polar contact '69 of relay 4WZ in a left-hand position, lower reverse winding R of relay AWZ, to This application of energy to the reverse winding R of relay 4WZ maintains the relay 4W2 energized to complete the operation of the switch machine 48M in the event that the relay 4R should be deenergized due to the operator changing his mind with regard to the establishment. of the route and therefore returning the entrance button IMNB, for example, to its normal position.

Upon the completion of the operation of the track switch-es 4TSA and lTSB to their reverse locked positions, the relay 4WP is energized-with the opposite polarity actuating its contacts to lefthand positions and causing its neutral contacts to be picked up. This energizes the reverse correspondence relay ARCR through the circuit above pointed out. The picking up of contact 59 of relay ARCR opens the stick circuit for the relay lLS so that with the'relay 4W2 still picked up opening back contact 51, the relay 4LS is entirely deenergized and its contacts drop away. The opening of front contacts 63 and of relay iLS removes energy from the switch machine 18M and the closure of the back contact 63 shunts the control wires through an obvious circuit.

If the switches tTSA and QTSB had already been in their reverse positions,'the reversecorrespondence relay @RCR would have been energized and would have remained energized so that the energization of relay QWZ by relay 4R would cause the immediate deenergization of relay 411$ at back contact 5?. Similar operation would occur upon the energization of either or both of the relays dAN and 4BN with the track switches TSA and fllTSB in normal positions, as the relay fiNCR, would remain energized so that the opening of back contact 51 of relay 4W2 would cause immediate deenergization of relay 4LS.

The above description points out the operation of the track switches QTSA and 'QTSB by the switch machine iSlVI which is controlled in ac cordance with the normal and reverse switch control relays lAN, and @BN. However, it is to be understood that the track switches 2TSA and ZTSB are operated by the switch machine ESM similarly controlled by the normal and reverseswitch control relays EAN, 2B and 2BN. Similarly, the switch machine 38M is controlled by the switch control relays 3N and 3R. Also,

Signal control With reference to Figs. 4A and 4B, it will be seen that with the entrance button lillNB in an actuated position and the exit relay IMXR picked up, energy can be applied to the signal clearing relay 'lfilG as soon as the correspondence relays for the various switches assume proper positions for the route in accordance with the set up condition of that route and as soon as the lock stick relays for all of the track switches in the route drop away indicating the completely locked condition of such track switches.

Assuming that each of the track switches in the route from the signal Nil to the signal I06 have been properly positioned and looked, as pointed out typically in connection with the crossover including track switches lTSA and lTSB, there is an energizing circuit closed for the relay IEHG from through a circuit including lever contact ill of entrance button IMSNB in a non-operated position, front contact 1| of relay liliiXR, back contact 32 of relay ELS, front contact 73 of relay (SNCR, front contact '14 of contact it of relay iL-S, back contact I? of relay GNCR, front contact '58 of relay lRCR, back contact id of relay iNCR, back contact of relay lLS, wire 85, back contact 82 of relay 3L3, back contact 83 of relay 3NCR, front contact 84 of relay tRCR, back contact 85 of relay lillXR, lever contact 8'6 of entrancebutton IDENB in an oper' ated position, winding of relay IOIG, to

- The: energization of the relay I 0IG changes the indication of the signal I 0| from stop to clear to allow the passage of a train over the I route thus set up.

Route locking as a train cannot occupy all of the track sections of a route at the same time upon entering such route, it is necessary to provide means for maintaining a route locked in advance of the trainv even after the entering signal has been returned to stop (either manually or automatically). It is of course to be understood that the releasing of the route locking in the absence of a train in the route may be contingent upon certain approach locking conditions as described in the above mentioned prior patent granted to E. C. Larry et al., Patent No. 2,125,242 dated July 26, 1938.

This type of route locking, conveniently termed directional rear releasing route locking, usually employs an east stick relay ES and a west stick relay WS for each of the track sections of the track layout, and these relays have circuits selected through the switch position repeating relays WP, the track relays T and the signal control relays G.

With reference to Figs. 3A and 33, it will be seen that the relays G, one for each of the signals of Figs. 4A and 4B are shown in block form at the left of Fig. 3A and at the right of Fig. 3B.

' Along the top of Figs. 3A and 3B are the switch position repeating relays WP and the track relays T-shown in block form. At the bottom of these Figs. 3A and 3B are shown the lock relays L, one for each track section, selected through contacts of thedirectional stick relays ES and WS, the

track relays T, and the contacts of the auxiliary switch machine control levers SML.

The directional stick relays ES and WS together with the lock relays L are normally energized by circuits readily apparent from the drawings, but in order to make the description entirely clear with regard to the operation of the system,

the operation of these directional stick relays will be pointed out in detail with regard to the route above established from which operation of the route looking for the various other routes will be understood by analogy.

With the above route set up, the track switch 3T5 is in a reverse position so that the polar contactsof relay 3WP are in left-hand positions, and similarly the track switches 4TSA and 4TSB are reversed While the track switches 'JTSA,

-5TSB and GT5 are in normal positions.

Under such conditions, the relay ISES is energized by a circuit closed from through a circuit including back contact of relay IUIG, front contact 9I of relay I2ES, wire 92, polar contact 93 of relay 5WP in a right-hand position, front contact 94 of relay 5WP, front contact of relay I5T,.windings of relay I 5ES, to

It is noted that the front stick contact 90 of relay I5ES shunts the front contact 95 of track relay I5T.- Also, the polar contact 91 of relay ZWP and front contact 98 provides a shunt circuit for the front contact SI of relay I2ES when the track switches ZTSA and ZTSB are reversed which eliminates the control of the relay IZES from the relay I5ES under such conditions. Also, it is noted that front contact 99 of relay MES over wire I00 shunts the contacts 93 and 94 of relay 5WP. In other words, the relay I5ES is not controlled by relay MES except when the track switches 5TSA and BTSB are reversed.

The relay MES is energized by a circuit closed from through a circuit including back contact IIO of relay I03G, wire III, front contact II2 of relay I5ES, wire II3, front contact H4 of relay 2WP and polar contact H5 of relay 2WP in a right-hand position in multiple with front contact II 6 of relay IZES, front contact II? of relay MT, winding of relay I IES, to It is noted that front stick contact N8 of relay MES shunts the front contact II! of relay MT, and contact II2 of relay I5ES is effective because the contacts of relay 4WP are reversed.

Relay I SES is energized by a circuit closed from through a circuit including back contact I20 of relay I04G, front contact I2I of relay MES, wire I22, front contact I23 of relay IGT, windings of relay IGES, to It is noted that front stick contact I 24 of relay IBES shunts front contact I 23 of relay IBT. Relay I 4ES has its contact I2l shunted from the control of relay IGES by contacts I25 and I26 of relay 5WP when the track switches STSA and STSB are reversed.

From the above description, it is seen that with the route established from signal I M to signal I06, the relay IBES is dependent for its energization upon the relay MES at front contact I2I, while the relay MES is in turn dependent upon the relay I5ES at front contact H2. The relay I5ES is dependent upon the deenergized condition of the relay IOIG at back contact 90. Thus, upon the clearing of the signal I M by the picking up of the relay IOIG, as above described, the relays I5ES, MES and IBES are successively deenergized in that order. The directional stick relays WS for the corresponding track sections are not deenergized, as they are dependent upon the clearing of the signal I 06 for the'opposite direction for their deenergization with this particular route set up, nor are these relays WS affected by the passage of a train in an eastbound direction through the route, as will be mentioned more in detail hereinafter.

With the directional stick relays ES and WS all picked up and the track sections unoccupied, the lock relays L for the various track sections are energized by their respective circuits. More specifically, lock relay I2L is energized by a circuit closed from through a circuit including front contact I21 of relay I2ES, front contact I28 of relay I2T, front contact I29 of relay IZWS, windings of relay I2L, lever contact I30 of lever 2SML in a non-operated position, to It is noted that front contact I3I of relay I2L applies negative potential to the left-hand terminal of the relay I2L to shunt out the lever contact I30 from the stick circuit for the relay I2L.

Lock relay I4L is normally energized by a circuit closed from through a circuit including front contact l32 of relay I 4WS, front contact I33 of relay MT, front contact I34 of relay MES, winding of relay ML, lever contact I35 of lever ZSML in a non-operated position, lever contact I36 of lever ISML in a non-operated position, lever contact I 31 of lever 5SML in a non-operated position, to stick contact I38 of relay I4L applies negative potential to the right-hand terminal of the relay ML to shunt out the lever contacts from the stick circuit for the relay ML.

The relay FL is energized by a circuit closed from through a circuit including front contact E39 of relay IEES, front contact 451 of relay HST, front contact i l! of relay IEWS, windings of relay IEL, lever contact 542 of lever SML in a non-operated position, lever contact 143 of lever ASML in a non-operated position, lever contact Hi l of lever- 3SML in a non-operated position, to It is noted that the stick contact I it; of relay lEL applies negative potential to the left-hand terminal of the relay [5L to shunt out the contacts of the levers SML from the stick circuit of relay l5L.

The lock relay [6L is energized by a circuit closed from through a circuit including front contact MS of relay IEWS, front contact 141 of relay HST, front contact MB of relay WES, windings of relay lBL, lever contact I59 of lever BSML in a non-operated position, to It is noted that the front contact it!) of relay lfiL applies negative potential to the right-hand terminal of the lock relay I61. to shunt out the contact 449 of lever SSML from the stick circuit of the lock relay IBL.

'The deenergization of the relays WES, MES and MES causes the deenergization of the lock relays 55L, ML and ML at open front contacts 139, I34 and 1 18 respectively.

As above mentioned, each track switch or crossover is provided with a lock stick relay LS which includes contacts of the lock relay L of the section (or sections) in which such switch is included. In other words, the dropping of any lock relay L locks all of the track switches included in its associated track section by opening the pick up and stick of their respective lock stick relays LS. The lock stick relay LS for a crossover of course includes contacts of two lock relays L inasmuch as the opposite ends of the crossover are in separate track sections, all of which has been typically illustrated in connection with the lock stick relay lLS of Fig. 2

which includes front contacts 55 and 5% of the lock relays I5L and ML respectively.

In brief, the clearingof the signal it?! upon the picking up of the signal control relay HHG deenergizes the directional stick relays for the eastbound direction for the route set up, and which relays in turn deenergize the lock relays L for each of their track sections so as to look all of the track switches in such route.

Not only does the dropping of the lock relay L for a section lock all of the track switches in such section by opening the pick up and stick circuits for the iock stick relays LS, but it also provides stick circuits for the switch control relays N and R of all the track switches in that section. This has been typically illustrated in connection with the control relays QINAIERNB for the track switches i-TSA and @TSB in Fig. 2 of the accompanying drawings.

With the switch control relay 4R picked up causing the track switches iTSA and GTSB to be reversed, then upon the dropping of lock relays ML and EL stick circuits are provided for the relay dR which maintain it energized under the various conditions to be pointed out in detail in connection with the passage of a train and the restoration of the route to normal.

One stick circuit for the relays QR is closed from through a circuit including back contact it! of relay ML, front contact i532 of relay 4R, back contact 953 of relay 4AN, center winding of relay flR, -back contact I54 of relay 4BN; to I The other stick circuit .for the relay 4R is closed from through'a circuit'including back contact 5555 of relay i513, frontcontact 56 of relay 3R, back contact i555 of relay iAN, middle winding of relay 6R, back contact I54 of relay @BN, to

In. a similar manner each of the N and R relays for the remaining track switches of the route are stuck up dependent upon their lock relays L. It will, of course, be apparent that if the reverse relay R for a track switch is for a single track switch instead of a crossover that it will have but a single stick'circuit instead of two, as pointed out in connection with the relay QR. Also, it might be mentioned in this connection that for a single switch there is but a single N relay and a single R relay. All of this route locking becomes effective after the establishment of the route and the clearing of the signal for such route, and in this way provides that the directional stick relays ES or WS and the lock relays L which repeat them are deenergized only for the track sections included in the route established.

Passage of a train.Let us assume that a train accepts the clear signal lili and proceeds through the route toward the signal I86. The entrance of the train into the track section including track relay EET deenergizes such track relay and opens the front contact 95 included in the pick up circuit for the directional stick relay BEES. Thus, the operator, as soon as he observes the proper indication on the control panel of the passage of the train into the track section in the rear of signal iEll, returns the entrance button HHNB to its normal at stop position which opens the energizing circuit for the relay HG at lever contact 86 (see Fig. 4A). The dropping of the relay it! G changes the indication of the signal H35 from clear to stop and also closes back contact 9G to prepare the pick up circuit for the relay lEiES (see Figs. 3A and 3B) but this relay MES cannot pick up by reason of the open front contact 95 of track relay I5T. In other Words, the operator returns the signal to stop but the directional stick relays in advance of the train remain deenergized. This holding deenergized of the relays ISES, MES and IGES for the route under consideration maintains the lock relays 55L, ML and lfiL dropped away so as to maintain the relays 3R, 5BN and 5N stuck up through their stick circuits which will be readily understood by analogy to the stick circuit pointed out in connection with the relay 4R of Fig-'2.

As the train passes through the route and leaves the track section including track relay I5T and enters the track section including track relay MT, the dropping of the track relay MT opens front contact Ill in the pickup circuit of the relay MES so that the relay MES is maintained deenergized although the relay iiiES is picked up upon the leaving of the train from the track section including the track relay I5T. In other words, as soon as the track relay l5T picks up, the relay itES is energized through its pick up circuit because the relay lGlG has been dropped away. The deenergization of the relay I iT maintains relays MES and ltES deenergized to hold the route in advance of the train, but the picking up of the relay EEES closes the pick up circuit for the lock relay ISL which in turn releases the stick circuits for the track switches in its section.

' The track switch 3T3 is entirely released because the relay 3R has its stick circuit open by the picking up of the relay I5L. One of the stick circuits for the relay AB is opened, but inasmuch as the track relay I 4T is still deenergized the other stick circuit for the relay 4R is still closed.

As the train passes into the track section including the track relay I6T, such track relay is dropped away holding the relay IEES deenergized although the relay MES picks up upon the picking up of track relay MT. The picking up of the relay MES releases the other stick circuit for the relay 6R and also releases a stick circuit for the relay 5BN (not shown). In other words, with the train on the track section I6T a route could be established from the signal I03 to the signal I05 although the train had not entirely passed out of the first route.

Assuming that the train entirely passes out of the route allowing the picking up of the track relay WT and the directional stick relay IGES, I

the lock relay I6L picks up releasing the relay 6N. Under such conditions the system has been restored tonormal conditions insofar as the deenergization of the self-selecting network is concerned and the picking up of various of the relays which are normally energized. However, it is to be understood that the track switches are left in their last operated positions until further manual control either'through the entrance-exit manipulation or by the auxiliary switch control levers. We may now consider some of the results effected by the maintaining stuck up of the N and R relays in the self-selecting network due to the presence oi a train.

Prevention of route pre-conditioning.Let us assume that the route from signal IM to signal I06 above described, is set up and that the train has just passed the signal I M so that the operator has returned the entrance button IOINB to its stop position. It might happen that the operator would desire to set up a conflicting route such as from the signal I05 to signal IM and to do this he actuates the entrance button I 05NB to an operated position followed by the actuation of the ex t button IIlIXB. However, any control resulting from such manipulation of the entranceexit buttons in conflict with the route between the signal IM and the signal I06 is prevented. Such prevention of the establishment of a conflicting route not only actually prevents the conflicting route frombeing set up but also prevents any of the devices from being positioned and maintained in such a way that the second route can be established following the passage of the train through thefirst route beyond the point of conflict.

For example, assuming that the entrance button I INB has been restored to normal so that the opening of contact 20 removes energy from all of the Z relays which may be depending upon it, such as the relay 6Z for the-route under consideration. Also, the exit relay I06XR is deenergized and drops away. But the relays BR, 43,

BN and 6N are stuck up by the route locking energization of relay IAZ and various of the circuits emanating from the entrance point.

In other words, any energy that may be applied by the operation of an entrance button fails to reach any Z relay beyond the point of conflict between the two routes by reason of an interlock which occurs at the point of conflict in the routes. The actuation of the exit button I 6IXB cannot pick up the exit relay I 0 IXR as there is no energy passed on to it by reason of the open back contact I6I of relay 5BN and I62 of relay 4R. Thus,

if the operator really desires such route from signal I05 to signal IOI to be established, he must operate the entrance button I05NB followed by the operation of the exit button IUIXIB following the passage of the train in the first route (from signal I0! to signal I06) beyond the point of confiict, which in this case will be as soon as the train leaves the track section MT.

Optional route selection.The system of the present invention is so organized that a preferred one of two routes between two points is set up when those two points are designated as entrance and exit points with the additional feature that the inferior of the two optional routes is selected and caused to be set up when there is a route conflicting with the preferred route. Such conflicting route may be set up ready for the passage of trafiic thereover or there may be a train in such conflicting route between its entrance point and the point of conflict with the preferred or superior of the optional routes. This automatic selection between two possible routes between two points is accomplished by positive circuit selections included in the self-selecting network and will perhaps be best understood by considering the operations involved.

Let us assume that the operator desires to set up a route from the signal I06 to the signal I02 with the system in its present normal condition. To do this he actuates the entrance button I06NB followed after a short interval of time by the actuation of the exit button I 02KB.

The operation of the entrance button I06NB closes a circuit for energizing the relay 532 from through a circuit including lever contact I63 in an operated position, back contact I64 of exit relay I06XR, back contact I65 of relay 6R, back contact I66 of relay 5R, winding of relay 532, to

When the relay 5BZ picks up a circuit is closed for the relay 2AZ from through a circuit including lever contact I63 in an operated position, back contact I64 of relay IOGXR, back contact I65 of relay 6R, back contact i66 of relay 5R, front contact I61 of relay 532, back contact I68 of relay 4BN, back contact I69 of relay 4AN, back contact I10 of relay 4AZ, wire I1I, back contact I12 of relay 3R, back contact I13 of relay 2R, windings of relay ZAZ, to

Upon the response of the relay ZAZ current is passed on from heel of contact I13 through front contact I14 of relay ZAZ so that the actuation of exit button I02XB closes contact I15 to complete the circuit through the relay IDZXR, and lever contact I16 in a non-operated position, to The picking up of the contacts of the exit relay IOZXR closes front contact I 11 to apply negative potential to the left-hand terminal of the exit relay I 02KB, so that the exit button I 02XB can be immediately released.

The picking up of the exit relay I02XR applies energy to the completion network for selectively energizing the N and R relays for the various track switches in the route to be set up.

More specifically, relay 2AN is energized by a circuit closed from through a circuit in cluding front contact I80 of relay IOZXR, front contact I8I of relay 2 AZ, lower winding of relay 2AN, back contact I82 of relay 2R, to

The response of the relay 2AN applies energy to the relay 3N through a circuit closed from (i-), through a circuit including front contact I80 of relay HlZXR, front contact I8I of relay 2AZ, front contact I83 of relay 2AN, lower winding of relay 3N, back contact I84 of relay 3R, to

The response of the relay 3N closes an energizing circuit for the relay 4R from through a circuit including front contact I80 of relay IIJZXR, front contact I8I of relay ZAZ, front con tact i233 of relay .ZAN, front contact I85 of relay 3N, wire 5%, back contact'I81 of relay QAZ, lowe'r'winding of relay R,'back contact 42 of relay iAN, back contact 43 of relay 4BN, to The picking up of the relay 4R passes energy on to energize the relay 5BN through a circuit closed from the back point of contact I81 of relay IAZ', through front contact I 88 of relay 4R, front contact I89 of relay 5 BZ, lower winding of relay 5BN, back contact 3i! of relay 5R, to

The picking up of the relay SBN passes energy on from the front point of contact I89 through frontcontact I95 of relay EBN, through lower winding of relay 6N, back contact 31 of relay SE, to

From the above, it is seen that the relays N and R for the various switches in the route to be set up from signal I06 to signal I82 are sequentially energized in accordance with the uniform cascade arrangement. Irrespective of the direction in which a route is to be set up this cascade arrangement of. the and R, relays causes them to pick up sequentially beginning from the exit end of the route and returning towards the entrance point.

Inasmuch as the selections for the energization of the relays N and R for the various track switches are determined by the Z relays, it is readily apparent that the track switches ZTSA and ZTSB are caused to be operated normal and the track switches ATSA and 4TSB are caused'to be operated reverse due to the fact that the relay ZAZ, is picked upin response to, the operation of the entrance button IOGN'B. This causes the route from the, signal I06 to the signal I92 to. be set up over the track switches ITSA andiTSB in reverse positions as the preferred route. The manner in which this is accomplished by causing the operation of the various track switches in re-I sponse to their N and R relays will be readily understood by analogy to the description pointed out in connection with such operation with reference to. Fig. 2 of the accompanying drawings.

It will also be understood how the route is looked upon the clearing of the signal and relays N and R, stuck up in accordance with the principles previously pointed out. I

If at the time that the operator actuated the entrance button IUBNB followed by. the operation of the exit, button IBZXB, a route had been set up between the signal IIlI and the signal I05, the route between signals I02 and I06 would have been set up, over the track switches 2TSA and 2TSB in reverse positions.

More specifically, if a route is set up between the signals IIII and I05, the relays 3R, IAN and 5AN are picked up. While the signal is still clear and the entrance button IBINB or entrancebutton IEJENB isstill in an operated position, these relays of the network are maintained picked up for such reasons, but after the entrance of the train into. such route, the entrance button controlling that route may then be restored to normal, so that these relays 3R, eAN and SAN are maintained picked up by reason of their stick circuits closed by their lock relays for the track section with which they "are included.

Therefore, upon the operation of the entrance button IUGNB, the relay ZAZ is not energized by reason of the fact that the relay MN is picked up. opening its back; contact I69 to prevent the passing of energy onto the relay 2AZ. However, the exit relay IIlZXR must be, energized and it is provided with a circuit which is closed from through a circuit including lever contact I63 of entrance button IOISNB in an operated position, back contact I64 of relay IMSXR, back contact I65 of relay 6R, back contact I65 of relay 5R, front contact I61 of relay 5132, back contact I9I of relay 4R, wire 152, back contact 993 of relay ZBN, back contact I34 of relay ZAN, back contact I14 of relay ZAZ, windings of relay lil2XR, exit contact I15 of exit button I02XB, lever contact I16 of entrance button IQZNB in a non-operated position, to

With the relay 2AZ deenergized, the exit relay itlZXR closes a pick upycircuit for the relay 2R from through a circuit including front contact I80 of relay IEZXR, back contact I8 I of relay ZAZ, lower winding of relay 2R, back contact I95. of relay 2AN, back contact I96 of relay 2BN, to

The pick up of the relay 2R. passes energy on from the back point of contact I8I through front contact I91 of relay 2R, wire I93, lowerwinding of relay QBN, backcontact I99 of relay 4R, to he. p ck p. o the lay 4BN pa ses n r y n from wire I98 through front contact208v of relay 4BN, a front contact I89. of relay 5BZ, lower Wind: ing of relay SBN, back contact 39 of relay 513, to (2 The picki p of the relay EBN passes en: ergy on through front contact I90 to the relay 6N as. previously explained.

Erom the above, it will thus be seen that the track switches 2TSA, and ZTSB are caused to be reversed and the track switches iTSA and iTSB are maintained in normal positions by reason of the fact that, a route has been set; up over a route which conflictswith. the, superior of two optional routes Similar operations. occur when a. route is to be set up from the signal I02 to the signal I86 (the opposite. direction from the optional routes above considered). but in such a case the superior route. is over the, track switches ZTSA and 2TSB reversed. However, there needs to be this explanation that there is no intervening track switch be-. tween the track switches. ZTSB and lTSB corresponding to the track switch 3T8 between the, track switches 2TSA and II-SA so: that the inferior route over the track switches fiTSA and ITSB in reverse positions is. not automatically set up, dueto traffic conditions with the chosen track layout. However, if the track circuits aredivid'ed so as to have an insulated joint between the track switches 2TSB and ATSB with or without an intervening turnouttrack switch, such automatic selection can readily be accomplished with re spect to thesetting up of a route from the signal I02 to the signal I05.

The same selection between optional routes may be accomplished manually for both directions of traffic 'as will be explained hereinafter, it first being desirable to point out why the track switches ZTSA and ZTSB are reversed upon the 

